KR20090028250A - Vehicular suspension for detecting sensor fault - Google Patents

Abstract

A vehicle suspension is provided to detect malfunction of the acceleration sensor by using additional software logic, not mechanical device. A vehicle suspension comprises shock absorbers(120FR,120FL) which are arranged in each wheel and generate damping force, a plurality of vertical acceleration sensors(130FR,130FL) measuring the vertical acceleration of vehicle, and a controller(190) detecting the malfunction of the vertical acceleration sensor. The vertical acceleration sensors include one or more front vertical acceleration sensors positioned in the front of the vehicle and one or more rear vertical acceleration sensor positioned in the rear of the vehicle.

Description

Vehicle suspension for detecting sensor faults {Vehicular suspension for detecting sensor fault}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle suspension and to a vehicle suspension capable of detecting a failure of an acceleration sensor.

In general, the suspension connects the axle to the body, and the shock absorber absorbs the free vibration of the spring and the stabilizer that prevents the vehicle from swinging from side to side. Stabilizer and the like.

Suspension characteristics of automobiles should be operated smoothly to improve riding comfort in normal driving, and hard to secure driving stability in uneven roads and high-speed driving. In addition, it should be possible to minimize the vibration of the vehicle body by absorbing all the shock generated according to the road surface conditions while driving.

Passive suspension is fixed to a constant value such as the spring constant of the spring, the damping force of the shock pressure shock absorber. The electronically controlled active suspension improves driving stability and ride comfort by controlling the height of the vehicle by controlling the spring constant, damping force, and circuit pressure of the air spring according to the driving speed and road conditions. It is an electronic control system for that purpose.

Suspension plays a very important role in securing the ride comfort and driving stability of the vehicle, and studies to improve riding comfort and active driving stability by using active suspension to overcome the performance limitations of the passive suspension system are conducted. It is becoming. Active suspensions include fully active suspensions and semi-active suspensions. Fully active suspensions are very good in performance while expensive, so semi-active suspensions are often used. The semi-active suspension system only changes the damping force of the shock absorber in real time according to road conditions and driving speeds, thereby improving driving stability and riding comfort. For example, the CDC (Continuous Damping Control) device, which is a kind of semi-active suspension, continuously controls the damping force to suit the situation by varying the area of the orifice through which the hydraulic pressure passes during the stretching and compression strokes.

In order for the active suspension to operate normally, the reliability of the main sensors constituting the suspension must be ensured. If the sensor malfunctions, not only will the ride quality be deteriorated, but also the stability may be impaired.

Korean Patent Laid-Open Publication No. 1999-0062746 calculates the difference between the output values of the wheel speed sensor and the acceleration sensor at predetermined intervals, calculates their ratios as the gradient coefficient of the acceleration sensor, and the calculated gradient coefficient is outside the range of the predetermined value. It is determined that there is an error in the surface acceleration sensor.

There is a need for a method to more efficiently detect failure of an acceleration sensor in an active suspension.

An object of the present invention is to provide a vehicle suspension device for detecting a failure of the acceleration sensor.

Suspension for a vehicle according to an aspect of the present invention is disposed on each wheel, a shock absorber for generating a damping force, a plurality of vertical acceleration sensors for measuring the vertical acceleration of the vehicle and the vertical acceleration measured from the plurality of vertical acceleration sensors, respectively The controller may control the damping force by using the controller, and obtain a center acceleration estimated from the measured vertical acceleration for each vertical acceleration sensor to detect a failure of each vertical acceleration sensor. The plurality of vertical acceleration sensors includes at least one front vertical acceleration sensor disposed at the front of the vehicle and at least one rear vertical acceleration sensor disposed at the rear of the vehicle. The controller detects a failure of the rear vertical acceleration sensor by comparing the time delay of the vertical acceleration measured by the rear vertical acceleration sensor and the vertical acceleration measured by the front vertical acceleration sensor.

According to another aspect of the present invention, there is provided a method for detecting a sensor failure of a vehicle suspension, which controls the damping force transmitted from the wheel by using the measured vertical acceleration. The sensor failure detection method includes obtaining a front vertical acceleration measured from a front vertical acceleration sensor disposed at the front of the vehicle, obtaining a rear vertical acceleration measured from the rear vertical acceleration sensor disposed at the rear of the vehicle, and time delayed. And averaging the front vertical acceleration and the rear vertical acceleration to detect a failure of the rear vertical acceleration sensor by using a difference between the rear vertical acceleration and the rear vertical acceleration.

It is easy to implement because the acceleration sensor can be detected by the addition of software logic without the need for additional electrical and mechanical devices. Rapid fault detection of the accelerometer ensures the reliability of the active suspension.

1 is an exemplary view showing a vehicle provided with a suspension device according to an embodiment of the present invention.

Referring to FIG. 1, each wheel is steered by the steering wheel 110. At each wheel, shock absorbers 120 _FL , 120 _FR , 120 _RL , and 120 _RR are arranged to provide damping force. Subscript FR denotes the right front wheel, FL the left front wheel, RR the right rear wheel, and RL the left rear wheel.

The vehicle body 105 is disposed with three vertical acceleration sensors 130 _FR , 130 _FL , 130 _RR for measuring vertical acceleration. The acceleration sensor is also called a G (gravity) sensor, and the vertical acceleration refers to an acceleration in a direction perpendicular to the traveling direction (or road surface) of the vehicle. Vehicle speed sensor 140 is arranged to measure vehicle speed.

Here, three vertical acceleration sensors 130 _FR , 130 _FL , and 130 _RR are illustrated, but the number or arrangement of the acceleration sensors may vary.

The vehicle body 105 is disposed with a lateral acceleration sensor 154 for measuring lateral acceleration and a longitudinal acceleration sensor 156 for measuring longitudinal acceleration. In addition, the vehicle body 105 may further include a roll acceleration sensor (not shown) for measuring roll acceleration and / or a pitch acceleration sensor (not shown) for measuring pitch acceleration.

The controller 190 disposed inside the vehicle body 105 receives signals from the vertical acceleration sensors 130 _FR , 130 _FL and 130 _RR and the vehicle speed sensor 140, and shock absorbers 120 _FL , 120 _FR and 120 _RL. , 120 _RR ) improves driving stability and ride comfort by changing the damping force to suit the driving conditions such as road conditions and driving speed. In addition, the controller 190 detects a failure of the vertical acceleration sensors 130 _FR , 130 _FL , 130 _RR , and takes appropriate measures or informs the driver accordingly.

2 is a block diagram of the suspension of FIG.

Referring to FIG. 2, the controller 190 includes an input interface unit 192, a processor 194, a sensor failure detection device 196, and an output interface unit 198. The input interface unit 192 receives signals measured from the vertical acceleration sensors 130 _FR , 130 _FL , 130 _RR , the vehicle speed sensor 140, the lateral acceleration sensor 154, and the longitudinal acceleration sensor 156. The processor 194 determines the attenuation force of each shock absorber 120 _FL , 120 _FR , 120 _RL , 120 _RR from the input sensor signals, and outputs each shock absorber 120 through the output interface 198. _FL , 120 _FR , 120 _RL , 120 _RR ). In addition, the processor 194 receives the failure of the vertical acceleration sensors 130 _FR , 130 _FL , and 130 _RR from the sensor failure detection device 196, and informs the driver of this.

The sensor failure detection device 196 detects a failure of the vertical acceleration sensors 130 _FR , 130 _FL , 130 _RR . Sensor failure detection device 196 using the measured values coming from each vertical acceleration sensor _{(130 FR, 130 FL, 130} RR) obtains a center of the acceleration of each vertical acceleration sensor _{(130 FR, 130 FL, 130} RR). A residual is defined from this central acceleration, and when the residual exceeds a threshold, it is diagnosed as a failure of the vertical acceleration sensors 130 _FR , 130 _FL , 130 _RR . In this case, the residual of the rear vertical acceleration sensor 130 _RR may be obtained in consideration of the time delay of the measured value of the front vertical acceleration sensors 130 _FR and 130 _FL .

The sensor failure detection device 196 estimates the center acceleration from the dynamic model of the vehicle and the measured vertical acceleration. The failure of each vertical acceleration sensor is detected from the center acceleration.

Now, a sensor failure detection method according to an embodiment of the present invention is described.

3 is a schematic diagram illustrating a vehicle model.

,

이라고 할 수 있다. 차량의 무게를 m, 각 타이어의 스프링 계수를 K_ri (i=1,2,3, 4), 각 차륜의 스프링 계수를 K_ui, 감쇠(damping) 계수를 C_ui라 하면 현가장치의 움직임을 다음 식과 같이 표현할 수 있다.Referring to FIG. 3, it is assumed for this model that the static and dynamic coefficients of friction of the elements constituting the suspension for linearization are fixed. In addition, the displacement in the vertical direction is very small, where the displacement at each corner is assumed to be independent. Because of this assumption, for any imprint α

,

It can be said. If the weight of the vehicle is m, the spring coefficient of each tire is K _ri (i = 1,2,3,4), the spring coefficient of each wheel is K _ui , and the damping coefficient is C _ui . It can be expressed as the following equation.

In this case, the inertia acting in the pitch and roll direction is I _XX , I _YY , and the transverse distance from the center of gravity to each wheel is w _i (i = 1,2,3,4) Then, the following equation is established.

는 중심 가속도,

는 롤 방향 가속도,

는 피치 방향 가속도이다. 이하에서 중심 가속도는 차량의 무게 중심에서 수직 가속도를 말한다. here,

Is the center acceleration,

Roll direction acceleration,

Is the pitch direction acceleration. Hereinafter, the center acceleration refers to the vertical acceleration at the center of gravity of the vehicle.

The above formula is summarized as follows for the center acceleration, roll direction acceleration, and pitch direction acceleration.

At this time, the lateral distance from the center of gravity to the wheels are all equal (w _i = w), and a sub-model representing the vertical acceleration applied to the corner of the vehicle body by formula (3). Obtained as follows.

4 is a schematic diagram illustrating a vehicle model in which three vertical acceleration sensors are disposed.

을

와

의 선형 보간(linear interpolation)에 의해 구하면 다음과 같은 관계식이 성립한다.4, the vertical acceleration of the rear wheel

of

Wow

By linear interpolation of, the following relation holds.

By substituting Equation 5 into Equation 4, the center acceleration estimated from each vertical acceleration sensor can be obtained as follows.

과

는 2개의 전방 수직 가속도 센서로부터 입력되는 측정된 수직 가속도 값,

은 후방 수직 가속도 센서로부터 입력되는 측정된 수직 가속도 값이고, 롤 가속도

및 피치 가속도

는 센서로부터 직접 입력 또는 동역학 모델로부터 추정이 가능하다. 따라서, 2개의 전방 수직 가속도 센서에 대한 중심 가속도

,

및 후방 수직 가속도 센서에 대한 중심 가속도

을 상기 수학식 6으로부터 얻을 수 있다.

and

Is the measured vertical acceleration value input from the two front vertical acceleration sensors,

Is the measured vertical acceleration value input from the rear vertical acceleration sensor, and roll acceleration

And pitch acceleration

It can be estimated directly from the sensor or from the dynamics model. Thus, center acceleration for two forward vertical acceleration sensors

,

Acceleration for front and rear vertical acceleration sensors

Can be obtained from Equation 6 above.

If the suspension has a sensor capable of measuring roll acceleration and pitch acceleration, the angular center acceleration can be directly obtained from the above equation.

If there are no sensors capable of measuring roll acceleration and pitch acceleration, then normal force applied to each wheel should be used to estimate roll acceleration and pitch acceleration. Lateral acceleration and longitudinal acceleration are required to estimate the vertical force. Lateral acceleration can be measured using a lateral acceleration sensor. If there is a longitudinal acceleration sensor, the longitudinal acceleration can be measured immediately. However, even when the longitudinal acceleration sensor is not installed, the estimated value can be obtained using the engine and brake information. In this case, it is assumed that the lateral acceleration value and the longitudinal acceleration value are received through the sensor.

When the vehicle is not running, the front and rear vertical forces F _zf and F _zr applied to the wheels by the load of the vehicle are distributed as follows.

However, when the longitudinal force is applied to the vehicle, the vertical force applied to the wheel by the longitudinal acceleration component a _x of the vehicle is modified as follows.

In addition, the amount of change in the vertical force distributed to the left and right by the lateral movement of the vehicle is determined by the roll stiffness K _{f φ} of the vehicle and the lateral acceleration a _y of the vehicle, as follows.

Therefore, the vertical force distributed to each wheel is as follows.

5 is a schematic diagram illustrating a vehicle model for pitch movement.

Referring to FIG. 5, a relational expression for pitch acceleration using this model is as follows.

Therefore, by substituting Equation 10 into Equation 11, the estimated pitch acceleration can be obtained.

6 is a schematic diagram illustrating a vehicle model for a roll motion.

Referring to FIG. 6, a relational expression for roll acceleration using this model is as follows.

Therefore, by substituting Equation 10 into Equation 12, the estimated roll acceleration can be obtained.

By applying the estimated pitch acceleration and the estimated roll acceleration to Equation 6, the center accelerations for three vertical acceleration sensors can be obtained.

The residual for each vertical acceleration sensor is defined as follows.

The first and second residuals r ₁ and r ₂ are residuals for two forward vertical acceleration sensors, respectively, and the third residual r ₃ is a residual for rear vertical acceleration sensors. If any one of the first, second and third residuals exceeds a preset threshold, it is detected as a sensor failure. .

Vehicle dynamics is used to estimate pitch acceleration and roll acceleration from longitudinal and lateral acceleration sensors. The center acceleration for each vertical acceleration sensor is estimated using the estimated pitch acceleration, roll acceleration, and the vertical acceleration measured from each vertical acceleration sensor. The estimated center accelerations detect the failure of each vertical acceleration sensor. By adding software without changing system components, sensor malfunctions can be detected, thereby ensuring the reliability of active suspensions.

7 is a flowchart illustrating a sensor failure detection method according to an embodiment of the present invention.

Referring to FIG. 7, measured vertical accelerations are respectively obtained from a plurality of vertical acceleration sensors (S210). The center acceleration for each vertical acceleration sensor is calculated (S220). In order to calculate the center acceleration, roll acceleration and pitch acceleration are first estimated using lateral acceleration and longitudinal acceleration. The residual is obtained from the center acceleration, and the failure of the vertical acceleration sensor is detected by determining whether the residual is within the allowable range (S230).

Now, the simulation results for the sensor failure detection method according to the present invention will be described.

8 is a graph showing a sensor input signal when traveling at 100 kph. 9 is a graph showing the residual for each vertical acceleration sensor in the steady state. Since the residuals for each vertical acceleration sensor do not all exceed a predefined threshold, it is determined that no failure is detected. It can be observed that the residual increases due to model uncertainty at the time of turning. 10 is a graph showing residual when a failure of the left front wheel FL vertical acceleration sensor occurs. When 0.5 g of error in the FL-side vertical acceleration sensor lasts from 20 to 25 seconds, it can be observed that the error affects the residual. The sensor failure detection device may also detect a FL vertical acceleration sensor whose residual exceeds a threshold as a failure. 11 is a graph showing residual when a failure of the right front wheel (FR) vertical acceleration sensor occurs. When 0.5 g of error in the FR vertical accelerometer lasts from 20 to 25 seconds, the residuals exceed the threshold, thereby detecting the failure of the FR vertical accelerometer.

The actual vehicle test results are now explained.

The actual vehicle uses a series of Sport Utility Vehicles (SUVs), collects signals entering an ECU (Engine Control Unit) through a bridge, modulates them through a FIU, which causes a malfunction, and sends them to RCP equipment. Configure. It is assumed that the failure of each vertical acceleration sensor does not overlap with each other, and the occurrence, duration, and size of the failure can be determined while driving.

12 is a graph showing a sensor signal during linear travel at a speed of 80 kph. This situation is set to check whether the sensor fault detection device satisfies the basic requirements. Fig. 13 is a graph showing the residuals in a situation where there is no failure when driving linearly at a speed of 80 kph. Since all residuals do not cross the threshold, no fault is detected. FIG. 14 is a graph illustrating a residual in failure of the RR vertical acceleration sensor during linear driving of 80 kph. It shows the residual when 0.3g malfunction occurs in the RR vertical acceleration sensor from 15 seconds to 20 seconds. Since the residual of the RR vertical acceleration sensor exceeds the threshold, it can be detected as a failure.

FIG. 15 is a graph showing a sensor signal when driving in a circle having a radius of 30 m at a speed of 40 kph. This situation is set to check whether the sensor failure detection device operates correctly even under normal driving conditions. Fig. 16 is a graph showing residuals in a situation where a circle having a radius of 30 m is driven at a speed of 40 kph. Since all residuals do not cross the threshold, no fault is detected. FIG. 17 is a graph illustrating failure residual of the FL vertical acceleration sensor in a circle driving having a radius of 30 m at a speed of 40 kph. It shows the residual when the malfunction of 0.3g occurs from 15 seconds to 20 seconds in the FL vertical acceleration sensor. Since the residuals of the FL accelerometer exceed the threshold, they can be detected as faults.

18 is a graph showing a sensor signal when driving on a block road at a speed of 30 kph. This situation is set to check whether the sensor failure detection device is affected by the ground condition. 19 is a graph showing residual when there is no malfunction when driving a block road at a speed of 30 kph. Since all residuals do not exceed the threshold, no fault is detected.

20 is a graph showing a sensor signal when driving on a dirt road at a speed of 30 kph. This situation is set up to check how the sensor fault detection device is affected when the ground conditions change. Fig. 21 is a graph showing the residuals in the situation of driving on a dirt road at a speed of 30 kph. Since all residuals do not cross the threshold, no fault is detected.

Fig. 22 is a graph showing sensor signals when slalom running at a speed of 50 kph. This situation is set to check whether the sensor failure detection device operates correctly even when the driver's input changes. Fig. 23 is a graph showing the residual in the zigzag running at a speed of 50 kph. Since all residuals do not cross the threshold, no fault is detected.

24 is a graph showing a sensor signal when driving on a bumpy road at a low speed. This situation is set to check whether the sensor fault detection device is affected by the bumps.

Fig. 25 is a graph showing the residuals in the situation of traveling on a bumpy road at a low speed. At this time, since the residual of the RR vertical acceleration sensor exceeds the threshold, it is detected as a failure of the RR vertical acceleration sensor. However, this is inconsistent with the actual situation. Therefore, there is a need to compensate for this problem.

Fig. 26 is a graph showing the residual when a malfunction of 0.4 g occurs from 16 to 17 seconds in the RR acceleration sensor during low-speed bump driving. The fault of the RR acceleration sensor exceeds the threshold between 16 and 17 seconds. However, a malfunction occurs in which a failure of the RR acceleration sensor is detected in some sections (between 22 seconds and 23 seconds). Therefore, there is a need to supplement this problem.

When the vehicle is driving over the bumps, it can be assumed that the front and rear wheels pass the same ground surface with a delay caused by the longitudinal distance between the vehicle speed and the wheels. Therefore, knowing the longitudinal distance between the vehicle speed and the wheel, the time delay can be calculated. If the vertical acceleration of the front wheel is delayed on the time axis by this time delay, it can be directly compared with the vertical acceleration of the rear wheel. Therefore, by calculating the difference between the delayed FR acceleration sensor signal and the current RR acceleration sensor signal by using this assumption, a new residual for detecting malfunction of the RR acceleration sensor can be obtained. This content is expressed as an expression as follows.

Here, T is a sampling time.

FIG. 27 is a graph showing residuals in a situation in which bumps are driven at a low speed using Equation (14). The fault is not detected because the residual of the RR vertical acceleration sensor does not exceed the threshold. This is consistent with the actual situation. Therefore, this additional logic can be used to compensate for the above problem.

FIG. 28 is a graph showing a residual when a malfunction of 0.4 g occurs from 16 seconds to 17 seconds in the RR vertical acceleration sensor while driving on a bumpy road at a low speed using Equation (14). Since the residuals of the RR vertical acceleration sensor exceed the threshold only between 16 and 17 seconds, the sensor failure detection device accurately diagnoses the malfunction of the sensor.

All of the above functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), or the like according to software or program code coded to perform the function. The design, development and implementation of the code will be apparent to those skilled in the art based on the description of the present invention.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, the present invention is not limited to the above-described embodiment, and the present invention will include all embodiments within the scope of the following claims.

1 is an exemplary view showing a vehicle provided with a suspension device according to an embodiment of the present invention.

2 is a block diagram of the suspension of FIG.

3 is a schematic diagram illustrating a vehicle model.

4 is a schematic diagram illustrating a vehicle model in which three vertical acceleration sensors are disposed.

5 is a schematic diagram illustrating a vehicle model for pitch movement.

6 is a schematic diagram illustrating a vehicle model for a roll motion.

7 is a flowchart illustrating a sensor failure detection method according to an embodiment of the present invention.

8 is a graph showing a sensor input signal when traveling at 100 kph.

9 is a graph showing the residual for each vertical acceleration sensor in the steady state.

10 is a graph showing residual when a failure of the left front wheel FL vertical acceleration sensor occurs.

11 is a graph showing residual when a failure of the right front wheel (FR) vertical acceleration sensor occurs.

12 is a graph showing a sensor signal during linear travel at a speed of 80 kph.

Fig. 13 is a graph showing the residuals in a situation where there is no failure when driving linearly at a speed of 80 kph.

FIG. 14 is a graph illustrating a residual in failure of the RR vertical acceleration sensor during linear driving of 80 kph.

FIG. 15 is a graph showing a sensor signal when driving in a circle having a radius of 30 m at a speed of 40 kph.

Fig. 16 is a graph showing residuals in a situation where a circle having a radius of 30 m is driven at a speed of 40 kph.

FIG. 17 is a graph showing faulty residuals of a FL vertical acceleration sensor in a circular drive having a radius of 30 m at a speed of 40 kph.

18 is a graph showing a sensor signal when driving on a block road at a speed of 30 kph.

19 is a graph showing residual when there is no malfunction when driving a block road at a speed of 30 kph.

20 is a graph showing a sensor signal when driving on a dirt road at a speed of 30 kph.

Fig. 21 is a graph showing the residuals in the situation of driving on a dirt road at a speed of 30 kph.

22 is a graph showing a sensor signal when zigzag running at a speed of 50 kph.

Fig. 23 is a graph showing the residual in the zigzag running at a speed of 50 kph.

24 is a graph showing a sensor signal when driving on a bumpy road at a low speed.

Fig. 25 is a graph showing the residuals in the situation of traveling on a bumpy road at a low speed.

Fig. 26 is a graph showing the residual when a malfunction of 0.4 g occurs from 16 to 17 seconds in the RR acceleration sensor during low-speed bump driving.

FIG. 27 is a graph showing residual in a situation where a bumped road is driven at a low speed using Equation (14).

FIG. 28 is a graph showing a residual when a malfunction of 0.4 g occurs from 16 seconds to 17 seconds in the RR vertical acceleration sensor in the state of driving a bumpy road at a low speed using Equation (14).

Claims (6)

A shock absorber disposed on each wheel to generate a damping force; A plurality of vertical acceleration sensors measuring vertical acceleration of the vehicle; And And a controller for controlling the damping force by using the vertical accelerations measured from the plurality of vertical acceleration sensors, and obtaining the center acceleration estimated from the measured vertical accelerations for each vertical acceleration sensor to detect failure of each vertical acceleration sensor. But The plurality of vertical acceleration sensors includes at least one front vertical acceleration sensor disposed at the front of the vehicle and at least one rear vertical acceleration sensor disposed at the rear of the vehicle, wherein the controller measures at the rear vertical acceleration sensor. And a time delay of the vertical acceleration measured by the front vertical acceleration sensor and the vertical acceleration measured by the front vertical acceleration sensor to detect a failure of the rear vertical acceleration sensor. The method of claim 1, And the controller detects a failure of each vertical acceleration sensor by comparing the residual with a threshold, and the residual is a difference between the average of the center accelerations of the corresponding vertical acceleration sensors and the center accelerations of the remaining mathematical acceleration sensors. The method of claim 1, The center acceleration is obtained by using the estimated roll acceleration and the estimated pitch acceleration. The method of claim 3, wherein And a lateral acceleration sensor for measuring lateral acceleration and a longitudinal acceleration sensor for measuring longitudinal acceleration, wherein the estimated roll acceleration and the estimated pitch acceleration are obtained using the lateral acceleration and the longitudinal acceleration. In the sensor failure detection method of a vehicle suspension for controlling the damping force transmitted from the wheel by using the measured vertical acceleration, Obtaining a front vertical acceleration measured from a front vertical acceleration sensor disposed in front of the vehicle; Acquiring rear vertical acceleration measured from a rear vertical acceleration sensor disposed at the rear of the vehicle; And  And detecting a failure of the rear vertical acceleration sensor by averaging the time-delayed front vertical acceleration and the rear vertical acceleration and using the difference between the rear vertical acceleration and the time delay. The method of claim 5, wherein And detecting a failure of the front vertical acceleration sensor from the rear center acceleration estimated using the rear vertical acceleration and the front center acceleration estimated using the front vertical acceleration.

Images